Screen conveyor



Aprll 7, 1959 -w. J. LUNDY ET AL 2,880,848

SCREEN coNvEYoR Filed May 14, 1958 n. 'i A A A DRI VE /VECHA/V/JM 0 'l Im l 'l' Y l////// MaM ATTORNEY United States Patent O SCREEN CONVEYORWarren J. Lundy, Elmhurst, and Kenneth I. Swan, Libertyville, Ill.,assignors to United States Rubber Company, New York, N.Y., a corporationof New Jersey Application May 14, 1958, Serial No. 735,324

4 Claims. (Cl. 198-131) This invention relates to screen conveyors and,more particularly, to screen conveyors suitable for carrying elastomericstock during a heating operation.

When conveying elastomeric stock such as during preheating prior toforming automative parts, it is necessary to provide a high stocktemperature with a uniform distribution of heat to provide uniformrelief of stresses in the stock occurring during processing. Priorconveyors have, in general, been unsuitable for such an application inthat the heat was not uniformly distributed or the conveyors weresubject to sagging or deformation.

It is an object of the present invention to provide a new and improvedscreen conveyor providing improved distribution of heat during a heatingoperation.

It is another object of the invention to provide a new and improvedscreen conveyor which is protected against permanent deformation due toexcessive stresses which may occur during normal operation.

In accordance with the invention, a screen conveyor comprises a pair oflongitudinal supporting members and transverse conveyor sectionsattached to said supporting members. Each of the conveyor sections has aconvex screen surface and a rigid member disposed beneath the screensurface and spaced therefrom with a clearance sufliciently small toprevent permanent deformation of the screen surface When subjected tostress greater than its elastic limit.

Referring now to the drawing:

Fig. 1 is a side view of a screen conveyor constructed in accordancewith the invention;

Fig. 2 is a plan View of the Fig. 1 conveyor; and

Fig. 3 is a side view to an expanded scale of the transverse conveyorslats of the Fig. 1 conveyor.

Referring now to Figs. 1 and 2, the screen conveyor comprises a pair ofside chains 11, 12 and sprocket drive means 13, 14 therefor. A suitabledrive motor `and gear box 15 is represented schematically in Fig. 2.Transverse conveyor sections are attached to the side chains.

Referring now to Fig. 3, each of the conveyor sections has a convexscreen surface 17 of substantially semicircular shape. A rigid memberpreferably comprising an inverted substantially V-shaped bar 18 isdisposed beneath the screen surface and is spaced therefrom with vaclearance c approximately equal to 1A the radius of the screen surface17 to allow air circulation between the screen surface and the bar 18and to prevent permanent deformation of the screen surface whensubjected to stress greater than its elastic limit.

As represented in Fig. 2 the bar 18 extends under the length of theconveyor section 16.

As represented in Fig. 3, the diameter of the screen surface issubstantially equal to the pitch of the chain links 11a. The base 19 ofeach slat is bolted to the corresponding chain link. The ends 20, 21 ofthe conveyor sections are in an overlapping relation to prevent stockICC from dropping between the conveyor sections and to allow motionaround a curve.

During operation elastomeric stock to be heated 1s placed on theconveyor as represented in Fig. 1. The stock is carried through an ovennot shown and air circulates uniformly around the stock because there isa minimum surface area of the conveyor in contact with the stock.Accordingly, a minimum of heat is dissipated by conduction away from thestock, thereby allowing ecient and uniform heating of the stock. 'Illecurved surface 17 provides a minimum contact area with the stock and yetprovides sucient strength to carry the stock. The inverted V-shaped bar18 provides strength for the conveyor section and prevents permanentdeformation of the screen surface when, for example, an operators handaccidently exerts a stress on the screen surface greater than itselastic limit and which would otherwise cause permanent deformation ofthe screen surface. Also, in the event the screen surface 17 is forceddown against the bar 18, there is a minimum contact surface between thescreen and the bar, minimizing heat dissipation.

While there has been described what is at present believed to be thepreferred embodiment of this invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention, and it is, therefore,aimed to cover all such changes and modifications as fall within thetrue spirit and scope of the invention.

Having thus described our invention, what we claim and desire to protectby Letters Patent is:

1. A screen conveyor comprising a pair of longitudinal supportingmembers; transverse conveyor sections attached to said supportingmembers, each of said sections having a convex screen surface and arigid member disposed beneath said screen surface and spaced therefromwith a clearance suciently small to prevent permanent deformation ofsaid screen surface when subjected to stress greater than its elasticlimit.

2. A screen conveyor comprising a pair of side chains and sprocket drivemeans therefor; transverse conveyor sections attached to said sidechains, each of said sections having a convex, substantiallysemi-circular screen surface and a rigid member disposed beneath saidscreen surface and spaced therefrom with a clearance approximately equalto one-quarter the radius of said screen surface to allow aircirculation between said screen surface and said rigid member and toprevent permanent deformation of said screen surface when subjected tostress greater than its elastic limit.

3. A screen conveyor comprising a pair of longitudinal supportingmembers; transverse conveyor sections attached to said supportingmembers, each of said sections having a convex screen surface and arigid, inverted substantially V-shaped member disposed beneath saidscreen surface and spaced therefrom with a clearance suiciently small toprevent permanent deformation of said screen surface when subjected tostress greater than its elastic limit.

4. A screen conveyor comprising a pair of side chains and sprocket drivemeans therefor; transverse conveyor sections attached to said sidechains, each of said sections having a convex, substantiallysemi-circular screen surface and an inverted substantially V-shapedmember disposed beneath said screen surface and spaced therefrom with aclearance approximately equal to one-quarter the radius of said screensurface to allow air circulation between said screen surface and saidrigid member and to prevent permanent deformation of said screen surfacewhen subjected to stress greater than its elastic limit.

No references cited.

